326
FXUS65 KBOI 071134
AFDBOI

Area Forecast Discussion
National Weather Service Boise ID
534 AM MDT Mon Sep 7 2026

.UPDATE...Updated aviation discussion.

&&

.KEY MESSAGES...

- Breezy and cooler today, with showers continuing in the
  north, but becoming sunny in the south.

- Warmer and drier Tuesday through Thursday.

- Cooling, breezy weather, Friday through Sunday, with showers
  possible in northern areas Saturday.

&&

.SHORT TERM /Through Wednesday Night/...
Issued 202 AM MDT MON SEP 7 2026
Cold front, with showers and isolated thunderstorms, passed
through western ID Sunday evening and will be out of our CWA
before sunrise. Strongest frontal gusts Sunday evening were from
the west 35 to 55 mph in the Snake Basin between Mountain Home
and Twin Falls. The main shower band was still over our eastern
CWA zones at 1 AM MDT. Showers in the Magic Valley will shift
east of the area by 3 AM MDT. A few trailing light rain showers
were evident on radar in western Valley County/ID and Baker
County/OR near the center of a weakening upper low. These
showers will continue in northern CWA mountains today as the
low moves off into MT. We also have a 20% chance of thunderstorms
in Valley County/ID this afternoon. Models bring a second upper
low from BC across north-central ID tonight. That low looks too
weak for more showers but it will continue cloudiness in our
northern zones. Meanwhile, southern zones will become sunny
today and mostly clear tonight. All areas will be about 10
degrees cooler than yesterday, except Valley County which was
already cool yesterday. Tonight looks cooler also, with lows in
the 30s in the mountains to mid 40s in the valleys. The cool and
still moist air, and lighter winds, will lead to areas of valley
fog overnight and early Tuesday morning. After the second upper
low moves out early Tuesday morning, weak upper ridging will
come in leading to warmer, drier weather Tuesday and Wednesday.
High temps Tuesday will be 5 to 10 degrees warmer than today,
and Wednesday another 5 degrees warmer, reaching the 80s in the
lower southern valleys.

&&

.LONG TERM /Thursday through Monday/...
Issued 202 AM MDT MON SEP 7 2026
The warm, dry weather will continue Thursday with high temps
well into the 80s in the lower valleys and 75 to 85 degrees
in the mountains. Later Thursday a new upper trough will dig
southward along the BC coast. The trough will push a dry surface
cold front southeastward through our CWA Thursday night. The
front will bring gusty winds from the west or northwest,
followed by cooler, breezy weather Friday through Sunday, with
Sunday likely as cool as today. The supporting upper trough
will bring a chance of showers to our northern mountain zones
Saturday and Sunday, with snow level near 8000 feet.

&&

.AVIATION /12Z Monday through Tuesday/...
Issued 524 AM MDT MON SEP 7 2026
Cold front has moved east of the area. Scattered light rain
showers in w-central Idaho today, with snow level 8kft MSL.
Slight chance thunderstorms 07/18Z to 08/00Z. Scattered clouds
elsewhere until 08/00Z then clear. Patchy fog/low stratus in
northern mountain valleys until 07/16Z, and again after 08/06Z.
Surface winds: SW-NW 5-15 kt this morning, then W-NW in the
afternoon. Winds aloft at 10kft MSL: W 20-25 kt.

KBOI...VFR. Scattered clouds near 8 kft MSL until sunset then
clear. Surface winds: NW 5-10 kt this afternoon, otherwise
variable less than 6 kt.

&&

.BOI WATCHES/WARNINGS/ADVISORIES...
ID...None.

OR...None.

&&

$$

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AVIATION.....MC
SHORT TERM...LC
LONG TERM....LC